N-tertiary-alkyl alkanesulfonamides



United States Patent 3 238,257 N-TERTIARY-ALKYL ALKANESULFONAMIDES Edward Cooper Ballard, Wilmington, DeL, and James Gordon Burt, Oxford, Pa., assignors to E. I. du Pont de Nemours and Company, Wilmington, DeL, a corporation of Delaware No Drawing. Filed Oct. 10, 1960, Ser. No. 61,371 2 Claims. (Cl. 260-556) This invention is directed to an improved petroleum distillate fuel containing an N-tertiary-alkyl alkanesulfonamide. The fuel shows significant anti-icing and anticorrosion properties as well as excellent carburetor detergency.

The operation of an internal combustion engine under cool, humid atmospheric conditions is usually accompanied by engine staliing. This effect, referred to as carburetor icing, is attributed to the formation of ice particles in the carburetor, especially on the throttle plate and surrounding throttle body walls. Ice formation at the edge of the throttle plate reduces air flow to the engine, thereby causing stalling, or the air bleeds or venturi may ice and stall the engine from excessively rich mixtures.

Another common occurrence of engine stalling and other malfunctions takes place at idling speeds in stop-andgo driving in heavy traific. This is due mainly to an accumulation of deposits on the walls of the carburetor throttle body just below the closed position of the throttle blade While the engine is idling, at a time when the air filter is relatively ineffective. Most contaminants enter "the carburetor from the crankcase breather vent which releases blow-by fumes which are trapped under the hood when the car is stopped. Other sources are exhaust fumes "from the car ahead and smoke and dust from the air. A common remedy is adjustment of idling speed, but this action only wastes gasoline.

Closely associated with the handling and storage of petroleum distillate fuels is the problem of corrosion in storage tanke, fuel lines, pipelines and other equipment used to contain these fuels. Corrosion is attributed to the fuels themselves which are acidic in nature, to the sulfur compounds always present in petroleum products and also to water which is introduced during the refining operations.

It is an object of the present invent-ion to provide a significantly improved petroleum distillate fuel composition. It is a further object of this invention to provide novel distillate 'fuel compositions containing N-tertiaryalkyl alkanesulfonamides. A still further object is to provide significant anti-icing and anti-corrosion properties in petroleum distillate fuel compositions. Another object is to provide said compositions which exhibit excellent carburetor detergency.

The sulfonamides utilized according to the present invention are derived from tertiary-alkyl amines, and possess significant properties to produce an improved fuel composition. The N-tertiary-alkyl hydro-carbon sulfonamides are more stable to oxidation and thereby do not form oxidized products which in turn cause gummy deposits is gasoline. In addition, the N-tertiary-alkyl alkanesulfonamides are clear liquids. The N-normal alkyl alkanesulfonamides, on the other hand, are heterogeneous pastes that tend to separate into different phases on standing. This undesirable property causes great inconvenience at the refinery Where the sulfonamides are blended with the gasoline. The N-tertiary-alkyl alkanesulfonamides can be pumped directly, While the N-normalalkyl alkanesulfonamides must be heated to form a hornogeneous mixture before pumping and blending.

More specifically, the present invention is directed to an improved distillate fuel containing a minor proportion 3,238,257 Patented Mar. 1, 1966 "ice of an N-tertiary-alkyl alkanesulfonamide having the structure RSO NHR wherein R is a saturated alkyl radical having 12 to 30 carbon atoms and may contain chlorine, or a mixture of such alkyl radicals, and R is a tertiaryalkyl group having 8 to 22 carbon atoms, or a mixture of such alkyl groups. R may be octyl, dodecyl, myristyl, cetyl, stearyl, eicosyl, myricyl or mixtures of alkyl groups having 12 to 14, 14 to 16, or 16 to 20 carbon atoms, hydrocarbon groups derived from white oil, paraffin Wax or petrolatum or mixtures of such hydrocarbon groups. R is derived from a tertiary-alkyl monoamine and has the structure where the tertiary carbon atom is bonded to the nitrogen atoms, and may be tertiary-octyl, tertiary-'nonyl or a mixture of tertiary alkyl groups having 12-14 carbon atoms or 18-21 carbon atoms. Representative examples of such compounds are N tertia'ry octyl stearylsul-fonamide, N- tentiary-ei-cosyl dodecyisulfonamide, N-tertiarydodecyl white oil-sulfonamide, and N-tertiary-C alkyl eicosyl-sulfonamide.

A preferred embodiment of the present invention is a distillate fuel containing a sulfonamide of the heretoforedefined structure RSO NHR wherein the sum of carbon atoms of R and R is 25 to 35. Representative preferred compounds are N-tert-iary-octyl white oil-sulfonamide, N- tertiary-nonyl white oil-sulfonamide, N-tertiary-C alkyl white oil-sulfonamide, and N-tertiary-dodecyl paraffin wax-sulfonamide.

These additives are significantly effective in reducing the stalling tendencies and prevention of corrosion in hydrocarbon distillate fuels boiling in the gasoline and fuel oil range, such as kerosene, gas oils, cracked gas oils, compression-ignition and internal combustion fuels, and the conventional burner and furnace oils.

The amount of sulfonamides to be added to the fuel ranges from 0.0005 to 0.03 weight percent, depending upon the size of the hydrocarbon molecule in the fuel and the particular benefit desired. In motor gasolines, usually about 0.001 to 0.01 percent is used. In heavier fractions such as kerosenes, diesel fuels or household burner fuels, somewhat higher concentrations may be required. Below 0.0005 percent, the effect of the sulfonamide on the mineral oil decreases. Above 0.03 percent, the effect levels off and does not increase. The use of higher concentrations is thus not economically advantageous.

The sulfonamides utilized according to the present invention may be prepared by any known methods for the preparation of sulfonamides. They are conveniently prepared by starting with the aliphatic hydrocarbon desired and reacting with gaseous sulfur dioxide and chlorine in the presence of actinic light to obtain the hydrocarbon sulfonyl chloride, as described in US. Patents 2,046,090 and 2,202,791. The hydrocarbon sulfonyl chloride thus obtained may be further reacted with the desired amine by conventional techniques, as set forth in US. 2,334,186.

Preferably the hydrocarbon sulfonyl chloride used for the preparation of the sulfonamides of the present invention is derived from the sulfochlorination of a commercially available petroleum hydrocarbon, such as No. 40 white oil, which is a highly acid-washed paratfinic petroleum fraction having an average of 16 to 20 carbon atoms, of the following inspection data:

Acid wash test, color 2.0 Specified gravity, 16 C./16 C 0.810 Distillation range, C.:

5% distilled 284 50% distilled 300 95% distilled 342 Viscosity at 100 F., SUS 36 Paraflin wax and petrolatum may also be used.

For the preparation of the sulfonamides, readily available tertiary-alkyl primary amines are preferred, of the formula Percent Spec. Grav.

Sulfur N-tert.-octyl white oil-sulfonamide. 4. 3 0. 914 N-tert.-nonyl white oil-sulfonamide 4. 3 0. 950 N-tert.dodecyl white oil-sulionamide... 4. 0. 903 N-tert.-C1s-zz alkyl white oil-sulionam e 3. 7 0. 908 N-tert.-dodecyl parafiin wax -sulf0namide 4. 8 0.5%(g1C50 G./

1 Containing 15% petrolatum.

Representative examples illustrating the present invention follow.

The anti-icing properties of the sulfonamides of the present invention were demonstrated in a 6-cylinder Chevrolet engine whose carburetor operated in an atmosphere of 40 F. and 95% relative humidity. Fuel ad ditive combinations were rated by the number of minutes of open throttle operation at 1800 rpm. under a load necessary to cause stalling while idling. With the use of commercial, winter-grade gasoline without anti-icing protection, stalling occurs within 0.5 to 1.25 minutes, whereas a rating of 4 minutes and more may be obtained with the use of the sulfonamide additive of the invention.

The base fuel used in this test had the following inspection data: ASTM D86 distillation 10%118 F., 20%-135 F., 50%252 F., and 90%339 F.; Reid vapor pressure 13.2 p.s.i.

Gasoline: Minutes to cause stall Base fuel 1.25

Base fuel-H lbs/M bbls. N-tert.-dodecyl white oil-sulfonamide 4.00 Base fuel|7.5 lbs/M bbls. N-tert.-dodecyl white oil-sulfonamide 4.00

The carburetor detergency properties of the sulfonamides of the present invention may be demonstrated by using a Lausen test engine equipped with a Tillotsen carburetor modified by inserting removable leaflets around the throttle plate. Throughout the test, a portion of the exhaust gases of a second single cylinder engine running at a constant 2500 rpm. is introduced into the test carburetor. The test engine was cycled one minute at open throttle under dynamometer load and then for two minutes at idle of 1100:100 rpm. for a period of two hours. At the conclusion of the test, the leaflets were removed and rated on the scale: 0 representing bright and shiny to representing very heavy black deposits.

The gasoline used was commercially available and had the following inspection data:

Comparison of the leaflets after using the base gasoline and gasoline containing a sulfonamide additive of the present invention demonstrates the cleaning power of the additive as shown in the following table:

Table I Fuel Rating Description 4 Pronounced black ridge adjacent to the throttle plate edge, streaking down side.

1. 5 Faint gray line in same location. no streaking.

Base gasoline Gasoline+151b./M bbls. of N- tert.-dodecyl white oil sul- Ionamide.

The alkanesulfonamides of the present invention are markedly more effective as anti-rust agents than the arylsulfonamides described in US. Patent 2,197,851. A widely accepted test for anti-rust properties in distillate fuels is the dynamic rust test as described in the US. Military quality test, MIL-I-250l7, wherein a carefully polished steel specimen is subjected to the corrosive action of an agitated mixture of 300 ml. of depolarized isooctane and 30 ml. of synthetic sea water at F. for a period of 20 hours. The relative abilities of the additives to prevent rusting are measured by the minimum concentration necessary to give a specimen free of rust under these conditions, or by comparison of the amount of rust formed at equal concentrations. The superiority of the sulfonamides utilized according to the present invention is illustrated in the following table:

The sulfonamide additives of the present invention are unexpectedly superior in anti-rust and corrosion prevention as well as in their remarkable detergent properties and anti-icing characteristics. Another desirable feature of the sulfonamides is their economical attractiveness, being prepared from commercially, readily available materials, low in cost.

In many instances the sulfonamides of the invention may promote the action of, or have their functions improved by, other surface-active materials such as carboxylic acids, amides, amines, heterocyclic compounds, salts of petroleum sulfonates, alkyl phosphate salts, ethyleneoxide condensates and other such surface-active substances.

Any of the heretofore-described N-tertiary-alkyl alkanesulfonamides may be substituted in the preceding examples to give essentially the same results. In addition, concentrations may be varied as described and conditions modified by one skilled in the art, this being within the scope of the present invention. Other variations and modifications will be obvious to those skilled in the art.

As many apparently widely different embodiments of this invention may be made without departing from the spirit and scope thereof, it is to be understood that this invention is not limited to the specific embodiments thereof except as defined in the appended claims.

The embodiments of the invention in which an eX- clusive property or privilege is claimed are defined as follows:

1. A compound of the formula RSO NHR wherein R is selected from the group consisting of an alkyl of from 12 to 30 carbon atoms and a chloro-alkyl of from 12 to 30 carbon atoms, and wherein R is a tertiary alkyl having from 8 to 22 carbon atoms and said tertiary alkyl is bonded to the nitrogen atom by the tertiary carbon atom.

2. A compound of the formula RSO NHR according to claim 1, wherein the sum of carbon atoms of R and R is from 25 to 35.

References Cited by the Examiner UNITED STATES PATENTS 6 2,197,851 4/1940 Dietrich 4458 2,236,168 3/1941 Dietrich 252-47.5 2,287,639 6/1942 Pings 260556 X 2,361,188 10/1944 Fox 260556 2,394,902 2/1946 Engelmann 260556 2,658,916 11/1953 Krems 260556 2,739,050 3/1956 Wisherd 4472 2,793,943 5/1957 Moore 4472 2,945,749 7/1960 Andress 4472 2,982,629 5/1961 Andress et al 4471 3,039,861 6/1962 Andress et al. 4471 3,119,830 1/1964 Burt 260556 X FOREIGN PATENTS 508,794 7/ 1939 Great Britain.

OTHER REFERENCES Scott et aL: J. Org. Chem., vol. 21, pp. 388-390 (1956).

WALTER A. MODANCE, Primary Examiner.

JULIUS GREENWALD, DUVAL T. MCCUTCHEN,

IRVING MARCUS, Examiners. 

1. A COMPOUND OF THE FORMULA RSO2NHR1, WHEREIN R IS SELECTED FROM THE GROUP CONSISTING OF AN ALKYL OF FROM 12 TO 30 CARBON ATOMS AND A CHLORO-ALKYL OF FROM 12 TO 30 CARBON ATOMS, AND WHEREIN R1 IS A TERIARY ALKYL HAVING FROM 8 TO 22 CARBON ATOMS AND SAID TERTIARY ALKYL IS BONDED TO THE NITROGEN ATOM BY THE TERTIARY CARBON ATOM. 